> Unfortunately, whereas before, he could rely upon the compiler staying> just about as stupid from release to release, he now has to contend> with compilers that get 'smarter' from release to release.

While it is true that many compilers continue to improve with each
release, the *implication* that the performance of a new release is
monotonically non-decreasing is false. It is not uncommon for new
compiler releases to have a ratio of performance improvements versus
performance regressions of about three to one.

Of course, SPEC performance is always monotonically non-decreasing,
even if the release must be postponed. It is possible that a code
fragment of a SPEC benchmark runs slower, but it must be offset by a
code fragment that improves by equal or greater amount, since the
emphasis is on the total sum gain.